Aircraft carry a number antennas for navigational, communication, and other purposes. However, the limited space on the outer surface of an aircraft may require placement of the multiple antennas in close enough proximity to each other to create radio interference between them. In particular, harmonics generated by one antenna may interfere with coincident frequencies in the frequency bands of other antennas. Moreover the various antennas project from the outer surface of the aircraft and introduce drag that interferes with the aerodynamic performance of an aircraft.